+/* Check the instruction in the slot is break */
+static int __kprobes __is_ia64_break_inst(bundle_t *bundle, uint slot)
+{
+ unsigned int major_opcode;
+ unsigned int template = bundle->quad0.template;
+ unsigned long kprobe_inst;
+
+ /* Move to slot 2, if bundle is MLX type and kprobe slot is 1 */
+ if (slot == 1 && bundle_encoding[template][1] == L)
+ slot++;
+
+ /* Get Kprobe probe instruction at given slot*/
+ get_kprobe_inst(bundle, slot, &kprobe_inst, &major_opcode);
+
+ /* For break instruction,
+ * Bits 37:40 Major opcode to be zero
+ * Bits 27:32 X6 to be zero
+ * Bits 32:35 X3 to be zero
+ */
+ if (major_opcode || ((kprobe_inst >> 27) & 0x1FF)) {
+ /* Not a break instruction */
+ return 0;
+ }
+
+ /* Is a break instruction */
+ return 1;
+}
+
+/*
+ * In this function, we check whether the target bundle modifies IP or
+ * it triggers an exception. If so, it cannot be boostable.
+ */
+static int __kprobes can_boost(bundle_t *bundle, uint slot,
+ unsigned long bundle_addr)
+{
+ unsigned int template = bundle->quad0.template;
+
+ do {
+ if (search_exception_tables(bundle_addr + slot) ||
+ __is_ia64_break_inst(bundle, slot))
+ return 0; /* exception may occur in this bundle*/
+ } while ((++slot) < 3);
+ template &= 0x1e;
+ if (template >= 0x10 /* including B unit */ ||
+ template == 0x04 /* including X unit */ ||
+ template == 0x06) /* undefined */
+ return 0;
+
+ return 1;
+}
+
+/* Prepare long jump bundle and disables other boosters if need */
+static void __kprobes prepare_booster(struct kprobe *p)
+{
+ unsigned long addr = (unsigned long)p->addr & ~0xFULL;
+ unsigned int slot = (unsigned long)p->addr & 0xf;
+ struct kprobe *other_kp;
+
+ if (can_boost(&p->ainsn.insn[0].bundle, slot, addr)) {
+ set_brl_inst(&p->ainsn.insn[1].bundle, (bundle_t *)addr + 1);
+ p->ainsn.inst_flag |= INST_FLAG_BOOSTABLE;
+ }
+
+ /* disables boosters in previous slots */
+ for (; addr < (unsigned long)p->addr; addr++) {
+ other_kp = get_kprobe((void *)addr);
+ if (other_kp)
+ other_kp->ainsn.inst_flag &= ~INST_FLAG_BOOSTABLE;
+ }
+}
+